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A. HAYDN KNAPP, OF NEVTON CENTER, MASSACHUSETTS, ASSIGNOR T() HIMSELF, AND GEO. W. TISDALE, 0F WALIOLE, MASSACHUSETTS.

SCISSORS.

Speccation of Letters Patent No. 31,849, dated March 26, 1861.

T o all whom 'it may concern:

Be it known that I, A. HAYDN KNAPP, of Newton Center, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Shears and Scissors; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, making part of i this specification.

Figure l, is a side 'view o f a pair of shears provided with my improvement, the blades being represented as closed together; Fig. 2, a similar view thereof, the blades being partially opened; Fig. 3, a like view, with the blades opened or separated to the full extent; Fig. et, a transverse section thereof, in the plane indicated by the line w m, Fig. 1; Fig. 5, View of a part detached.

Like letters designate corresponding parts in all the figures;

The object of my invention is to produce a drawing cut of one blade on the other, in such a manner that it may be uniform, or irregular, as may be desired, for general or specific purposes; or to produce the drawing cut wholly in one portion of the movement, in closing the blades, and not at all in the other portion thereof. At the same time, a further object is to effect these results in a manner the most convenient, simple, and superior, in all respects, practicable. I accomplish these objects by a construction substantially as represented in the drawings.

First, instead of pivoting the two blades A, B, at a fixed point on both, I locate the pivot D, in the ordinary position as respects the cutting edges of the blades, and attach it immovably to the lower blade B, while the requisite extent of drawing movement to be given to the upper blade A, is allowed by means of a straight slot C, therein, nearly.

or exactly parallel with the cutting edge a, thereof, and fitting so as to slide freely but closely over the said pivot D. Second, for the purpose of producing the desired draw'- ing motion of the upper blade A, I employ another, curved, slot F, either in the shank of the upper blade A, or in a projecting plate thereon; (as represented in the drawl ings and this slot slides over, and is guided by, a stationary studor pin, G, attached to the shank of the lower blade B. By giving this slot F, different degrees, directions and forms of curvature, I produce all the desired varieties of drawing movement required to be given to the upper blade A, as expressed above. Thus, to illustrate by reference to the drawings, let Fig-3, represent the shears opened to the full extent; then if it is desired that there shall be less of the drawing cut in the firsthalf of the closing motion of the blades, and more in the last half, or near the points of the blades, the slot F, will be curved substantially as shown; and when the blades are half closed, as in Fig. 2, the position of the pivot D, in the slot C, shows that not one half of the length of the slot C, has been passed along said pivot, leaving the greater portion Y to be traversed in finally closing the blades,

to the position shown in Fig. l; the movenient of the slot C, over the pivot D, indicating the amount of drawing cut. In a similar way, any desired amount or manner of drawing cut may be shown, to be practicable, by varying the form and position of the curved slot F.

The only imperfection, or inconvenience, of any consequence, attending the simple construction above specified, is owing to the friction of the sides ofthe slots C, F, respectively upon the pivot D, and pin G. To obviate this, and, at the same time, to provide for keeping the blades properly tightened together, in the usual manner, I make the pivot D, and pin G, as screws, to be screwed into the lower blade D; and over that part of each, which is to be between the 'sides of the said slots, I place anti-friction sleeves 7, f, (Figs. 4, and 5,) fitting accurately within the slots, and around the screw pivot and pin, but so as to readily turn within and around them respectively, as the slots move over the pivot and pin. Thus these sleeves answer as bushes, to prevent the wearing of the sides of the slots, and pivot, and pin; and greatly diminishing the friction, thereby rendering the working of the shears, or scissors, more free and easy.

vI contemplate the application of the above described invention, to all kinds of shears and scissors, for all purposes to which they are applicable.

I do not claim giving a drawing cut to one blade of shears, or scissors, upon the other blade, nor do I claim the mere use of a slot and pin to produce this or any other motion; but

What I claim as my invention and desire to secure by Letters Patent, is-

l. The combination of the guide slot C, and pivot D, With the curved slot F, and

5 pin G, for producing any regular, or irregular drawing out desired, substantially in the nanner and for the purposes herein speci- 2. The bush sleeves f, f, applied to, and in i combination-With, the screw pivot D, pin 10 G, and the slots C, F, substantially as and for the purposes herein set forth.

The above specification signed by ine, this 19th day of October, 1860.

A. HAYDN KNAPP. Witnesses:

Jol-IN OBRIEN, CHAS. S. LINCOLN. 

